Elisabetta Pagani1, Maria A. Rocca1, Paolo Preziosa1, Sarlota Mesaros2, Bruno Colombo3, Mark A. Horsfield4, Andrea Falini5, Giancarlo Comi3, Massimo Filippi1
1Neuroimaging Research Unit, Institute of Experimental Neurology, San Raffaele Scientific Institute and Vita-Salute San Raffaele University, Milan, Italy, Italy; 2Clinic of Neurology, Faculty of Medicine, University of Belgrade, Belgrade, Yugoslavia; 3Department of Neurology, San Raffaele Scientific Institute and Vita-Salute San Raffaele University, Milan, Italy, Italy; 4Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom; 5Department of Neuroradiology, San Raffaele Scientific Institute and Vita-Salute San Raffaele University, Milan, Italy, Italy
In 113 multiple sclerosis (MS) patients and 35 healthy subjects, we calculated the angle between the principal diffusion direction and the cortical surface within each voxel of the brain cortex. It has previously been suggested that, in normal mature GM no preferential direction for diffusion exists, because of the cellular structures components that run both parallel (dendrites) and perpendicular (neurons and neuritis) to the cortex. MS patients (particularly those with the progressive disease clinical phenotypes) had an increased number of GM voxels with an angle close to 90 degrees, suggesting a degeneration of the structures running perpendicular to the cortical surface.